I was reading a few studies and this story -
www.familyeducation.com
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Some pregnant women may believe that environmental factors may play a role in what sex baby they have, while others look at their family trees. Whether you're having a baby for the first time or the fourth, we all really know that it's a matter of science.
The cells in our bodies are made up of 46 chromosomes that are grouped by pairs. Each pair has one chromosome from the mother and one from the father. Each sex cell carries half of the chromosomes. When it comes to the mother's eggs, chromosome 23 is always X. For the father's sperm, chromosome 23 can be either X or Y.
“The sperm determines the sex of a baby depending on whether they are carrying an X or Y chromosome. An X and Y combine to make a boy, while an XX make a girl," says Dr. Joel Gator Warsh, a Southern California-based integrative pediatrician.
Although it is the man's sperm that ultimately determines the sex of a baby, is it a coincidence that some women give birth to only boys while others only have baby girls? Math and science have a lot to say about it!"
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However, Langdon also references the Newcastle University study, published in Evolutionary Biography that showed that men are more likely to have sons if they have more brothers but are more likely to have daughters if they have more sisters. It suggests that an as-yet-undiscovered gene controls whether a man’s sperm contains more X or more Y chromosomes, which affects the sex of his children. Looking at how sperm cells impact the sex of the baby is key to unraveling why some women have only boys and others have only girls."
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If the sperm is said to define the sex of the child - would the male hormonal profile during conception influence the gender ? (i.e. this is just speculation - but would a higher-progesterone male lean towards a specific sex of a baby being born ?)
I notice that when I tell women that I have sisters they find that a lot more attractive than when I tell them I have brothers ... is there something subconsciously going on here ? That they may want a daughter so are my "genetics" important here ?
blogs.scientificamerican.com
"A few months ago, I read an article about a family with 14 children, all boys. That is a lot of boys! My first thought was what their grocery bills must be.
Refining the probability a little bit, there are about 105 boys born for every 100 girls, so about 51.2 percent of babies are boys. The probability, then, of 14-boy families among all 14-child families, is (.51214), which is about 0.0085 percent. Rounding that to the nearest order of magnitude, we would expect about 1 in 10,000 14-child families to have only boys.
After working out that probability, I had a new question: how many 14-child families are there in this? If there are more than 10,000, it seems likely that there are some 14-boy families out there. Even if there are only a few thousand 14-child households, it wouldn’t be too surprising to have a 14-boy family."
Family in Michigan with 14 consecutive born sons - the 15th and 16th child of this family were both girls
And then this study which examines how fetuses of different sex respond to the mother taking progesterone during pregnancy
www.nature.com
"We investigated the fetal effects of natural progesterone administration in early pregnancy using a clinically realistic large animal model and time-frame for progesterone administration. The ovine fetus at D75 gestation is developmentally is equivalent to the 15-week human fetus. We showed that maternal progesterone administration increased progesterone concentrations only in the male fetus. This male-specific effect was also seen in female and male co-twins. We therefore focussed on the effects of this increase of fetal progesterone concentrations in the male fetuses. Investigation of the readouts of pituitary and testicular function during fetal life suggests that maternal progesterone supplementation has effects on the male fetus reproductive axis development/function in early gestation. In addition, investigating circulating hormones, where progesterone is an intermediary in their synthesis, showed an increase in 11-dehydrocorticosterone in male fetuses."
"We don’t know why the male fetus increases progesterone in response to maternal administration, while the female fetus does not. There may be several explanations for this, including sexually dimorphic placental progesterone transport and metabolism. However, we chose to use in silico analysis of the fetal liver to look at potential hepatic metabolic explanations. We found sexually dimorphic expression of hepatic progesterone metabolising enzymes, with fetal males having lower expression than fetal females. This data is from D90 fetuses and so it is not clear how relevant the finding is at D75 gestation. However, it highlights that the sex differences seen in response to maternal progesterone administration is likely to be due to sexually dimorphic expression of progesterone metabolising enzymes."
It seems that male and female fetuses have completely different responses (even for sets of twins of each) to the mother taking progesterone during the pregnancy ?
How should we decipher this ? Can we say that a male fetus with higher progesterone is more likely to not occur in a miscarriage and develop with no birth defects since maybe we can say the baby develops healthier with higher progesterone ? How can we explain the female fetus response ?
AND
Given that fetuses dependent on sex respond differently to a mother taking progesterone - would actions taken in the short time span after being conceived decide the sex of the child ? Very interesting thoughts ...
What do users think ? I noticed I have known many families in my lifetime with kids who were all one sex or who were all mostly one sex ... I wonder if there is a defining factor in the time during and after conception that decides this ?
Why Do I Keep Having Girls (Or Boys)? Genetics and Gender
Find out why you keep having girls or boys and how genetics influences gender and sex of your baby!
"
Some pregnant women may believe that environmental factors may play a role in what sex baby they have, while others look at their family trees. Whether you're having a baby for the first time or the fourth, we all really know that it's a matter of science.
The cells in our bodies are made up of 46 chromosomes that are grouped by pairs. Each pair has one chromosome from the mother and one from the father. Each sex cell carries half of the chromosomes. When it comes to the mother's eggs, chromosome 23 is always X. For the father's sperm, chromosome 23 can be either X or Y.
“The sperm determines the sex of a baby depending on whether they are carrying an X or Y chromosome. An X and Y combine to make a boy, while an XX make a girl," says Dr. Joel Gator Warsh, a Southern California-based integrative pediatrician.
Although it is the man's sperm that ultimately determines the sex of a baby, is it a coincidence that some women give birth to only boys while others only have baby girls? Math and science have a lot to say about it!"
"
However, Langdon also references the Newcastle University study, published in Evolutionary Biography that showed that men are more likely to have sons if they have more brothers but are more likely to have daughters if they have more sisters. It suggests that an as-yet-undiscovered gene controls whether a man’s sperm contains more X or more Y chromosomes, which affects the sex of his children. Looking at how sperm cells impact the sex of the baby is key to unraveling why some women have only boys and others have only girls."
"
If the sperm is said to define the sex of the child - would the male hormonal profile during conception influence the gender ? (i.e. this is just speculation - but would a higher-progesterone male lean towards a specific sex of a baby being born ?)
I notice that when I tell women that I have sisters they find that a lot more attractive than when I tell them I have brothers ... is there something subconsciously going on here ? That they may want a daughter so are my "genetics" important here ?
What Are the Odds of a Family with 14 Boys?
I heard about a 14-boy Michigan family, so I crunched some numbers
"A few months ago, I read an article about a family with 14 children, all boys. That is a lot of boys! My first thought was what their grocery bills must be.
Refining the probability a little bit, there are about 105 boys born for every 100 girls, so about 51.2 percent of babies are boys. The probability, then, of 14-boy families among all 14-child families, is (.51214), which is about 0.0085 percent. Rounding that to the nearest order of magnitude, we would expect about 1 in 10,000 14-child families to have only boys.
After working out that probability, I had a new question: how many 14-child families are there in this? If there are more than 10,000, it seems likely that there are some 14-boy families out there. Even if there are only a few thousand 14-child households, it wouldn’t be too surprising to have a 14-boy family."
Family in Michigan with 14 consecutive born sons - the 15th and 16th child of this family were both girls
And then this study which examines how fetuses of different sex respond to the mother taking progesterone during pregnancy
Early pregnancy maternal progesterone administration alters pituitary and testis function and steroid profile in male fetuses - Scientific Reports
Maternal exposure to increased steroid hormones, including estrogens, androgens or glucocorticoids during pregnancy results in chronic conditions in offspring that manifest in adulthood. Little is known about effects of progesterone administration in early pregnancy on fetal development. We...
www.nature.com
"We investigated the fetal effects of natural progesterone administration in early pregnancy using a clinically realistic large animal model and time-frame for progesterone administration. The ovine fetus at D75 gestation is developmentally is equivalent to the 15-week human fetus. We showed that maternal progesterone administration increased progesterone concentrations only in the male fetus. This male-specific effect was also seen in female and male co-twins. We therefore focussed on the effects of this increase of fetal progesterone concentrations in the male fetuses. Investigation of the readouts of pituitary and testicular function during fetal life suggests that maternal progesterone supplementation has effects on the male fetus reproductive axis development/function in early gestation. In addition, investigating circulating hormones, where progesterone is an intermediary in their synthesis, showed an increase in 11-dehydrocorticosterone in male fetuses."
"We don’t know why the male fetus increases progesterone in response to maternal administration, while the female fetus does not. There may be several explanations for this, including sexually dimorphic placental progesterone transport and metabolism. However, we chose to use in silico analysis of the fetal liver to look at potential hepatic metabolic explanations. We found sexually dimorphic expression of hepatic progesterone metabolising enzymes, with fetal males having lower expression than fetal females. This data is from D90 fetuses and so it is not clear how relevant the finding is at D75 gestation. However, it highlights that the sex differences seen in response to maternal progesterone administration is likely to be due to sexually dimorphic expression of progesterone metabolising enzymes."
It seems that male and female fetuses have completely different responses (even for sets of twins of each) to the mother taking progesterone during the pregnancy ?
How should we decipher this ? Can we say that a male fetus with higher progesterone is more likely to not occur in a miscarriage and develop with no birth defects since maybe we can say the baby develops healthier with higher progesterone ? How can we explain the female fetus response ?
AND
Given that fetuses dependent on sex respond differently to a mother taking progesterone - would actions taken in the short time span after being conceived decide the sex of the child ? Very interesting thoughts ...
What do users think ? I noticed I have known many families in my lifetime with kids who were all one sex or who were all mostly one sex ... I wonder if there is a defining factor in the time during and after conception that decides this ?
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